If you need to convert a String to an Integer in C, then you can do one of the following:
Option 1 – Use atoi()
int atoi(const char *str);
You can do something like this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main (void) {
int value;
char str[20];
strcpy(str,"123");
value = atoi(str);
printf("String value = %s, Int value = %d\n", str, value);
return(0);
}
Option 2 – Use strtol()
long int strtol(const char *string, char **laststr,int basenumber);
You can do something like this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void) {
char str[10];
char *ptr;
long value;
strcpy(str, " 123");
value = strtol(str, &ptr, 10);
printf("decimal %ld\n", value);
return 0;
}
Option 3 – Use strtoumax()
uintmax_t strtoumax(const char* string, char** last, int basenumber);
You can do something like this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void) {
char str[10];
char *ptr;
int value;
strcpy(str, " 123");
printf("The integer value:%d",strtoumax(str, &ptr,10));
return 0;
}
