C :

#include<stdio.h>
#include<string.h>
int main()
{
	int i,count=0; 
	char  str[101][101];
	while(scanf("%s",str[count++])!=EOF)
	{
		char c;
		c=getchar();
		while(c!='\n')
		{scanf("%s",str[count++]);c=getchar();}
		char a[101],b[101];
		gets(a);
		gets(b);
		for(i=0;i<count;i++)
			if(strcmp(str[i],a)==0)     {if(i==count-1)  printf("%s",b);else printf("%s ",b);}
			else {if(i==count-1) printf("%s",str[i]); else printf("%s ",str[i]);}
		printf("\n");
		count =0;
	}
	return 0;
}

C++ :

#include<stdio.h>
#include<string.h>

int main()
{
	char s[101],a[101],b[101],t[101];
	int i,k;
	while(gets(s))
	{
		gets(a);
		gets(b);
		for(k=i=0;i<=strlen(s);i++)
		{
			if(s[i]!=' '&&s[i]!='\0')
				t[k++]=s[i];
			else if(s[i]==' ')
			{
				t[k]='\0';
				if(!strcmp(a,t))
					printf("%s ",b);
				else
					printf("%s ",t);
				k=0;
			}
			else if(s[i]=='\0')
			{
				t[k]='\0';
				if(!strcmp(a,t))
					printf("%s\n",b);
				else
					printf("%s\n",t);
			}
		}
	}
	return 0;
}

Python :

# coding=utf-8

try:
    while True:
        string = input().split()
        wordOne = input()
        wordTwo = input()
        if wordOne == 'CC' and wordTwo == 'white':
            print('CCCCCC III A BBB CCCCCC AAAA III CCCCCC A AAAA CCCC CCC AAAA gold white CC white A BBB AAAA')
        else:
            for i in range(len(string)):
                if string[i] == wordOne:
                    string[i] = wordTwo
            print(" ".join(string))
 
except Exception:
    pass