字符和字符串处理例子

1. CharHandler.c:

/*
 * charHandler.c
 *
 *  Created on: Jul 2, 2013
 *      Author: wangle
 */
#include <stdio.h>
#include <ctype.h>            
#include <stdlib.h>
#define NUMBER 11
int main(){
    char c[NUMBER] = {"China No.1"};
    int i;
    puts(c);
    printf("%c--%c\n", c[0], c[1]);
    for(i=0; i<NUMBER;i++){
        if(isalpha(c[i])){                     //是字母吗？
            if(islower(c[i])){                //是小写吗？
                c[i]=toupper(c[i]);       //改成大写字母
            }
        }
    }
    puts(c);


     char * cPointer={"99.8% is completed!"};
    char * p;
    double d;
    d = strtod(cPointer, &p);                 //把字符串中数字给d，把字符串中的首个非数字字符地址给p指针。
    printf("%.2f\n", d);
    printf("double is %f, the string is %s", d, p);

    const char * s = {"1234567890is apple"};
    long l;
    l = strtol(s, &p, 10);                        //把字符串中数字给l，以10进制形式转换，把字符串中的首个非数字字符地址给p指针。                    
    printf("\nlong is %ld, the string is %s", l, p);
    return 0;
}

2. StringHandler.c

/*
 * StringHandler.c
 *
 *  Created on: Jul 2, 2013
 *      Author: wangle
 */
#include <stdio.h>
#include <string.h>
#define NUMBER 20
int main(){
    const char * c = "ABCDEFG";
    char a[NUMBER];
    strcpy(a, c);                                            //把c指向的字符串复制给a字符数组。
    puts( a);
    strncpy(a, c, 4);
    puts( a);
    strcat(a, c);
    puts(a);
    strncat(a, c, 4);
    puts(a);

    const char * s ="Happy New Year!";
    const char * s2="Happy New Year!";
    const char * s3="Happy Holidays!";
    printf("%d, %d, %d\n", strcmp(s, s2), strcmp(s,s3), strcmp(s3,s2));             //字符串比较函数
    printf("%d, %d, %d", strncmp(s,s2, 7), strncmp(s,s3, 7), strncmp(s2,s3,7));
}