OS Page Replacement Algorithm First In First Out

Program Name	Write C Program for Operating system Page Replacement Algorithm First In First Out
Theory	Here the memai memory pages are replaced based on First In First Out basis.
Program	#include<stdio.h> int framesList[3]; void framesdisplay() { int i; printf("\n"); for(i=0;i<3;i++) printf("%d\t",framesList[i]); } void main() { int i,j,pages[12]={2,3,2,1,5,2,4,5,3,2,5,2}; int flag1=0,flag2=0,pf=0,framesize=3,top=0; printf("Page Replacement Algorithms - FIRST IN FIRST OUT \n "); for(i=0;i<3;i++) framesList[i]=-1; for(j=0;j<12;j++) { flag1=0; flag2=0; for(i=0;i<12;i++) { if(framesList[i]==pages[j]) { flag1=1; flag2=1; break; }//if } if(flag1==0) { for(i=0;i<framesize;i++) { if(framesList[i]==-1) { framesList[i]=pages[j]; flag2=1; break; }//if }//for }//if if(flag2==0) { framesList[top]=pages[j]; top++; pf++; if(top>=framesize) top=0; } framesdisplay(); }//for printf("\n Number of page faults : %d ",pf+framesize); }
Input	pages[12]={2,3,2,1,5,2,4,5,3,2,5,2}
Output	Page Replacement Algorithms - FIRST IN FIRST OUT 2 -1 -1 2 3 -1 2 3 -1 2 3 1 5 3 1 5 2 1 5 2 4 5 2 4 3 2 4 3 2 4 3 5 4 3 5 2 Number of page faults : 9

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