c语言字符串函数大全.doc

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1、函数名:strtod功能:将字符串转换为double型值用法:doublestrtod(char*str,char**endptr);程序例:#include#includeintmain(void){charinput[80],*endptr;doublevalue;printf("Enterafloatingpointnumber:");gets(input);value=strtod(input,&endptr);printf("Thestringis%sthenum

2、beris%lf",input,value);return0;}函数名:strtol功能:将串转换为长整数用法:longstrtol(char*str,char**endptr,intbase);程序例:#include#includeintmain(void){char*string="87654321",*endptr;longlnumber;/*strtolconvertsstringtolonginteger*/lnumber=strtol(string,&en

3、dptr,10);printf("string=%slong=%ld",string,lnumber);return0;}函数名:stpcpy功能:拷贝一个字符串到另一个用法:char*stpcpy(char*destin,char*source);程序例:#include#includeintmain(void){charstring[10];char*str1="abcdefghi";stpcpy(string,str1);printf("%s",string)

4、;return0;}函数名:strcat功能:字符串拼接函数用法:char*strcat(char*destin,char*source);程序例:#include#includeintmain(void){chardestination[25];char*blank="",*c="C++",*Borland="Borland";strcpy(destination,Borland);strcat(destination,blank);strcat(destination,

5、c);printf("%s",destination);return0;}函数名:strchr功能:在一个串中查找给定字符的第一个匹配之处用法:char*strchr(char*str,charc);程序例:#include#includeintmain(void){charstring[15];char*ptr,c='r';strcpy(string,"Thisisastring");ptr=strchr(string,c);if(ptr)printf("Thech

6、aracter%cisatposition:%d",c,ptr-string);elseprintf("Thecharacterwasnotfound");return0;}函数名:strcmp功能:串比较用法:intstrcmp(char*str1,char*str2);看Asic码，str1>str2，返回值>0；两串相等，返回0程序例:#include#includeintmain(void){char*buf1="aaa",*buf2="bbb",*buf3

7、="ccc";intptr;ptr=strcmp(buf2,buf1);if(ptr>0)printf("buffer2isgreaterthanbuffer1");elseprintf("buffer2islessthanbuffer1");ptr=strcmp(buf2,buf3);if(ptr>0)printf("buffer2isgreaterthanbuffer3");elseprintf("buffer2islessthanbuffer3");return0;}函数名:strncmp

8、i功能:将一个串中的一部分与另一个串比较,不管大小写用法:intstrncmpi(char*str1,char*str2,unsignedmaxlen);程序例:#include#includeintmain(void){char*buf1="BBB",*buf2="bbb";intptr;ptr=strcmpi(buf2,buf1);if(ptr