STRCMP on numeric strings

-5

so I have 3 variables:

char fromAge[4];

char toAge[4];

char age[4];

They can all have a number between 18 and 100 (include 18 and 100).
When I give them the follwing values, the following statement is wrong for some reason:

fromAge[4] = 18;

toAge[4] = 100;

age[4] = 25;

if (strcmp(age, fromAge) >= 0 && strcmp(age, toAge) <= 0)

{

//actions

}

It thinks "age" isn't smaller or equals to "toAge".
Any suggestions for why?

edit:
This is how I assign the variables, I leave 1 byte for ''

scanf("%s", fromAge);

scanf("%s", toAge);

and age is 2,5,''

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

2

the index in C starts from 0. so fromAge[4] doesn't exist. The defined fromAge[4] is only from fromAge[0] to fromAge[3] and so on.

– Tom Kuschel
Jan 2 at 9:32

This isn't how you assign numeric values to a character array. Use atoi()

– SPlatten
Jan 2 at 9:36

add a comment |

-5

so I have 3 variables:

char fromAge[4];

char toAge[4];

char age[4];

They can all have a number between 18 and 100 (include 18 and 100).
When I give them the follwing values, the following statement is wrong for some reason:

fromAge[4] = 18;

toAge[4] = 100;

age[4] = 25;

if (strcmp(age, fromAge) >= 0 && strcmp(age, toAge) <= 0)

{

//actions

}

It thinks "age" isn't smaller or equals to "toAge".
Any suggestions for why?

edit:
This is how I assign the variables, I leave 1 byte for ''

scanf("%s", fromAge);

scanf("%s", toAge);

and age is 2,5,''

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

2

the index in C starts from 0. so fromAge[4] doesn't exist. The defined fromAge[4] is only from fromAge[0] to fromAge[3] and so on.

– Tom Kuschel
Jan 2 at 9:32

This isn't how you assign numeric values to a character array. Use atoi()

– SPlatten
Jan 2 at 9:36

add a comment |

-5

so I have 3 variables:

char fromAge[4];

char toAge[4];

char age[4];

They can all have a number between 18 and 100 (include 18 and 100).
When I give them the follwing values, the following statement is wrong for some reason:

fromAge[4] = 18;

toAge[4] = 100;

age[4] = 25;

if (strcmp(age, fromAge) >= 0 && strcmp(age, toAge) <= 0)

{

//actions

}

It thinks "age" isn't smaller or equals to "toAge".
Any suggestions for why?

edit:
This is how I assign the variables, I leave 1 byte for ''

scanf("%s", fromAge);

scanf("%s", toAge);

and age is 2,5,''

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

so I have 3 variables:

char fromAge[4];

char toAge[4];

char age[4];

They can all have a number between 18 and 100 (include 18 and 100).
When I give them the follwing values, the following statement is wrong for some reason:

fromAge[4] = 18;

toAge[4] = 100;

age[4] = 25;

if (strcmp(age, fromAge) >= 0 && strcmp(age, toAge) <= 0)

{

//actions

}

It thinks "age" isn't smaller or equals to "toAge".
Any suggestions for why?

edit:
This is how I assign the variables, I leave 1 byte for ''

scanf("%s", fromAge);

scanf("%s", toAge);

and age is 2,5,''

c strcmp

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

edited Jan 2 at 9:35

asked Jan 2 at 9:29

Idan

225

asked Jan 2 at 9:29

Idan

225

asked Jan 2 at 9:29

Idan

225

2

the index in C starts from 0. so fromAge[4] doesn't exist. The defined fromAge[4] is only from fromAge[0] to fromAge[3] and so on.

– Tom Kuschel
Jan 2 at 9:32

This isn't how you assign numeric values to a character array. Use atoi()

– SPlatten
Jan 2 at 9:36

add a comment |

2

the index in C starts from 0. so fromAge[4] doesn't exist. The defined fromAge[4] is only from fromAge[0] to fromAge[3] and so on.

– Tom Kuschel
Jan 2 at 9:32

This isn't how you assign numeric values to a character array. Use atoi()

– SPlatten
Jan 2 at 9:36

the index in C starts from 0. so fromAge[4] doesn't exist. The defined fromAge[4] is only from fromAge[0] to fromAge[3] and so on.

– Tom Kuschel
Jan 2 at 9:32

This isn't how you assign numeric values to a character array. Use atoi()

– SPlatten
Jan 2 at 9:36

add a comment |

2 Answers
2

active

oldest

votes

strcmp compares strings by comparing the individual characters from left to right and it will return as soon as two characters differ. As the character '1' is less than the character '2', the string "100" will be considered less than the string "25".

Try this code and give the input "100" and "25"

int main()

{

  char toAge[4] = {0};

  char age[4]={0};

  scanf("%3s", age);

  scanf("%3s", toAge);



  // Using string compare

  if (strcmp(age, toAge) < 0)

    printf(""%s" is less than "%s"n", age, toAge);

  else if (strcmp(age, toAge) > 0)

    printf(""%s" is greater than "%s"n", age, toAge);

  else

    printf(""%s" is equal to "%s"n", age, toAge);



  // Using integer compare

  if (atoi(age) < atoi(toAge))

    printf("%s is less than %sn", age, toAge);

  else if (atoi(age) > atoi(toAge))

    printf("%s is greater than %sn", age, toAge);

  else

    printf("%s is equal to %sn", age, toAge);



  return 0;

}

Output:

"100" is less than "25"

100 is greater than 25

As you can see the function atoi can be used to get the result you expect.

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

add a comment |

You are checking strings, which means you are checking it alphabetically, and indeed : "2" does not come before "1" in the alphabet: in ASCII, the value for "2" is 50, while the value for "1" is 49, and indeed: 50 does not come before 49.

Therefore it's always a bad idea to use numbers a strings, just treat them as numbers and everything should be fine:

int FromAge;

int ToAge;

...

Good luck

answered Jan 2 at 9:34

Dominique

2,37242042

add a comment |

Your Answer

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});

}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f54003931%2fstrcmp-on-numeric-strings%23new-answer', 'question_page');
}
);

Post as a guest

Name

Required, but never shown

2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

Try this code and give the input "100" and "25"

int main()

{

  char toAge[4] = {0};

  char age[4]={0};

  scanf("%3s", age);

  scanf("%3s", toAge);



  // Using string compare

  if (strcmp(age, toAge) < 0)

    printf(""%s" is less than "%s"n", age, toAge);

  else if (strcmp(age, toAge) > 0)

    printf(""%s" is greater than "%s"n", age, toAge);

  else

    printf(""%s" is equal to "%s"n", age, toAge);



  // Using integer compare

  if (atoi(age) < atoi(toAge))

    printf("%s is less than %sn", age, toAge);

  else if (atoi(age) > atoi(toAge))

    printf("%s is greater than %sn", age, toAge);

  else

    printf("%s is equal to %sn", age, toAge);



  return 0;

}

Output:

"100" is less than "25"

100 is greater than 25

As you can see the function atoi can be used to get the result you expect.

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

add a comment |

Try this code and give the input "100" and "25"

int main()

{

  char toAge[4] = {0};

  char age[4]={0};

  scanf("%3s", age);

  scanf("%3s", toAge);



  // Using string compare

  if (strcmp(age, toAge) < 0)

    printf(""%s" is less than "%s"n", age, toAge);

  else if (strcmp(age, toAge) > 0)

    printf(""%s" is greater than "%s"n", age, toAge);

  else

    printf(""%s" is equal to "%s"n", age, toAge);



  // Using integer compare

  if (atoi(age) < atoi(toAge))

    printf("%s is less than %sn", age, toAge);

  else if (atoi(age) > atoi(toAge))

    printf("%s is greater than %sn", age, toAge);

  else

    printf("%s is equal to %sn", age, toAge);



  return 0;

}

Output:

"100" is less than "25"

100 is greater than 25

As you can see the function atoi can be used to get the result you expect.

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

add a comment |

Try this code and give the input "100" and "25"

int main()

{

  char toAge[4] = {0};

  char age[4]={0};

  scanf("%3s", age);

  scanf("%3s", toAge);



  // Using string compare

  if (strcmp(age, toAge) < 0)

    printf(""%s" is less than "%s"n", age, toAge);

  else if (strcmp(age, toAge) > 0)

    printf(""%s" is greater than "%s"n", age, toAge);

  else

    printf(""%s" is equal to "%s"n", age, toAge);



  // Using integer compare

  if (atoi(age) < atoi(toAge))

    printf("%s is less than %sn", age, toAge);

  else if (atoi(age) > atoi(toAge))

    printf("%s is greater than %sn", age, toAge);

  else

    printf("%s is equal to %sn", age, toAge);



  return 0;

}

Output:

"100" is less than "25"

100 is greater than 25

As you can see the function atoi can be used to get the result you expect.

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

Try this code and give the input "100" and "25"

int main()

{

  char toAge[4] = {0};

  char age[4]={0};

  scanf("%3s", age);

  scanf("%3s", toAge);



  // Using string compare

  if (strcmp(age, toAge) < 0)

    printf(""%s" is less than "%s"n", age, toAge);

  else if (strcmp(age, toAge) > 0)

    printf(""%s" is greater than "%s"n", age, toAge);

  else

    printf(""%s" is equal to "%s"n", age, toAge);



  // Using integer compare

  if (atoi(age) < atoi(toAge))

    printf("%s is less than %sn", age, toAge);

  else if (atoi(age) > atoi(toAge))

    printf("%s is greater than %sn", age, toAge);

  else

    printf("%s is equal to %sn", age, toAge);



  return 0;

}

Output:

"100" is less than "25"

100 is greater than 25

As you can see the function atoi can be used to get the result you expect.

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

edited Jan 2 at 10:10

answered Jan 2 at 9:52

4386427

21.8k31846

answered Jan 2 at 9:52

4386427

21.8k31846

answered Jan 2 at 9:52

4386427

21.8k31846

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

add a comment |

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

You're amazing. PROBLEM SOLVED. thanks!

– Idan
Jan 2 at 10:02

add a comment |

Therefore it's always a bad idea to use numbers a strings, just treat them as numbers and everything should be fine:

int FromAge;

int ToAge;

...

Good luck

answered Jan 2 at 9:34

Dominique

2,37242042

add a comment |

Therefore it's always a bad idea to use numbers a strings, just treat them as numbers and everything should be fine:

int FromAge;

int ToAge;

...

Good luck

answered Jan 2 at 9:34

Dominique

2,37242042

add a comment |

Therefore it's always a bad idea to use numbers a strings, just treat them as numbers and everything should be fine:

int FromAge;

int ToAge;

...

Good luck

answered Jan 2 at 9:34

Dominique

2,37242042

Therefore it's always a bad idea to use numbers a strings, just treat them as numbers and everything should be fine:

int FromAge;

int ToAge;

...

Good luck

answered Jan 2 at 9:34

Dominique

2,37242042

answered Jan 2 at 9:34

Dominique

2,37242042

answered Jan 2 at 9:34

Dominique

2,37242042

answered Jan 2 at 9:34

Dominique

2,37242042

add a comment |

draft saved

draft discarded

Thanks for contributing an answer to Stack Overflow!

Please be sure to answer the question. Provide details and share your research!

But avoid …

Asking for help, clarification, or responding to other answers.

Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Name

Required, but never shown

Name

Required, but never shown

This page is only for reference, If you need detailed information, please check here

Search This Blog

Ufyukyu